[winswitch] network load

Antoine Martin antoine at nagafix.co.uk
Thu Aug 28 12:35:00 BST 2014

On 28/08/14 17:09, Bob Tennent wrote:
> I've just realized that when I attach to a remote xpra
> server, I'm getting 250kB/s network load, even if nothing is
> happening; when I detach, the network load goes to zero. Is
> this normal? Using xpra-0.14.3 on Centos 6.
The answer is: it depends..
I believe that you now have sound forwarding enabled using a not
terribly efficient codec (maybe flac?). This used to be disabled by
default on CentOS only.
Turn off sound forwarding to see if that's the case.
If you want to disable this behaviour, either edit /etc/xpra/xpra/conf,
or to do it for a single user:
echo speaker=no >> ~/.xpra/xpra.conf

The next question that usually comes is to ask why we send sound data
when no sound is being played through the virtual sound card (ie: not an
application that uses sound), and the answer is that at the software
level, we just can't tell the difference so we have to send it all the
time. (also because we can't start playing sound quickly enough to start
it on demand, at least not all platforms)

Just for completeness: another possibility is that the application you
forward does repaint the screen even when nothing changes, some badly
written applications do that - and if you use a non-video encoding, this
would cause a fairly constant bandwidth usage.
Similarly, some browsers will repaint pretty much the whole page as soon
as you hover over a link anywhere..
In this case, you can minimize the window to confirm (minimized windows
do not cause any traffic)
You can also visualize how many pixels are being received per second on
the "Graph" pane of the "Session Info" dialog.


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